docs: def has_pkgs_signed_with(self, allowed_keys):
          """
          Check signature of packages installed in image.
          Raises exception when
  
          * rpm binary is not installed in image
          * parsing of rpm fails
          * there are packages in image that are not signed with one of allowed keys
  
          :param allowed_keys: list of allowed keys
          :return: bool
          """
  
          if not allowed_keys or not isinstance(allowed_keys, list):
              raise ConuException("allowed_keys must be a list")
          command = ['rpm', '-qa', '--qf', '%{name} %{SIGPGP:pgpsig}\n']
          cont = self.run_via_binary(command=command)
          try:
              out = cont.logs_unicode()[:-1].split('\n')
              check_signatures(out, allowed_keys)
          finally:
              cont.stop()
              cont.delete()
          return True